SIMULTANEOUS IDENTIFICATION OF STRUCTURAL DAMAGES AND MOVING FORCES FROM OUTPUT-ONLY MEASUREMENTS

摘要

A simultaneous identification method on structural damages and moving forces from output-only measurements is proposed in this paper,in which the damage factors are used as optimization variables only.All the response sensors in a structure are divided into two arrays.One array,named as load-sensor(LS),is selected for identifying moving forces from the structural responses recorded by LS.The others are named as objective-sensor(OS)used to define an objective function for structural damage detection.As an inverse problem,the moving forces are first identified from the LS measured responses of the structure with damage factors.The structural responses at all sensors are calculated by using the identified moving forces as a forward problem.The calculated responses at all the OS are extracted and compared with the corresponding measured ones.The Frobenius-norm of distance between the measured and calculated responses at all the OS is used to define an objective function on simultaneous identification of moving forces and structural damages.When the objective function is minimum as an optimization problem,the obtained damage factors are the structural damage detection results and the corresponded moving forces are the identified ones simultaneously.In order to assess the accuracy and the feasibility of the proposed method,a beam-like truss bridge subjected to moving forces were taken into account for numerical simulation.The illustrated results show that the method can simultaneously identify the structural damages and moving forces with a good accuracy and better robustness to noise.Some related issues are also discussed and recommended.